As for social infrastructures such as a lot of bridges and tunnels that have been constructed in various places since the high economic growth age of postwar days, deterioration is serious. Taking action to the deterioration of infrastructures is desirable. In this study, we aim to develop the robot that can inspect cracks and corrosion in steel bridge substructures. A four-wheel driving robot for trial purposes has been created with the aid of analysis using software DYMOLA. The robot can climb vertically on a steel wall. Strong permanent magnets are installed on the edge parts in the wheels. This robot does not fall by gravitation when it climbs a steel wall or runs along the ceiling upside down. The running performance of the robot is examined by the experiment.